So I've heard the JCW tuning kit exhaust (which I have) is 2.3" .. (I really need to just get under the car and measure it myself... /sigh )
I've also read your thoughts on the thermal dynamics side of the exhaust discussion 3" DP to 2.5" CB. While I want to avoid the 3" vs 2.5" discussion entirely (there are already several threads on this), I wanted to get your take on mating up a 3" DP to the JCW catback (under the assumption that the 3" to 2.5" argument is true and valid to keep this thread on point). It's rather close to the 2.5" and I don't have the experience or physics background to know the difference in volume/cooling on 2.5" vs 2.3". I'm sure lengths play into this somehow... Also keep in mind I think the JCW has a resonator (along with the second cat; I'm doing this from memory, so if I'm mispeaking, I'm sure someone will jump in).

Simply, am I truly shooting myself in the foot by even attempting to keep the JCW CBE given my desire to get a larger, less restrictive DP?

(As aside, I welcome other constructive opinions as well... but given the DP would have to be custom made given the 3" to 2.3" transition I'm suggesting... I'm uniquely curious to hear from those in the 3" to 2.5" camp even though I'm claiming to be seated squarely on the fence (( and it hurts! )) ).


(and the vehicle is a January 08 MCS w/ JCW tuning kit)

 

Mr Pro,

THis is the problem I have. These two connections are pretty funky. I dont ahve the tooling to make them which is why I cant offer you an actual bolt on catback or a bolt on downpipe. I can offer you a catback and downpipe with a loose flange so your exhaust shop can install it for you, if you get a full setup from me though it will be a bolt on.

Look at the DP (90 angle piece). That flare is way to close to the bend so i cant get my tooling to grip the pipe, i can only grip a straight piece not at a bend.

Tubing here in the states comes in 1/4" sizing. When you have .3 you now have a metric exhaust. IF this car is an english car then I would think it would have a standard exhaust vs metric. Sooo this leads me to beleive that the OEM system is not made in england. Most likely one of bmw's subcontractor makes it.

 

To paraphrase, to ensure I've got this right ... the issue is that where the JCW CBE is positioned, you would be required to do a 3" to 2.x" transition and flare on a 90 degree (or really close to it) angle (on the DP) .. which is not possible.
Correct? (this make good sense to me)

<shrug> Who knows ... I thought I read somewhere it was 2.3".. no idea who MINI sources it through; just know it's OEM'd through MINI and I've grown to really like the sound... it's not too loud but growls when you get on it... with no drone.

 

Yup you are correct. When you mass produce something iyou have special dies made , if your only going to move a few etc, the tooling cost is not worth it.